
    [[nodiscard]] constexpr auto xx() const noexcept { return vector<T, 2>(x, x); }
    [[nodiscard]] constexpr auto xy() const noexcept { return vector<T, 2>(x, y); }
    [[nodiscard]] constexpr auto yx() const noexcept { return vector<T, 2>(y, x); }
    [[nodiscard]] constexpr auto yy() const noexcept { return vector<T, 2>(y, y); }